1. Field of the Invention
The present invention relates to a solid electrolytic capacitor and a method of production the same.
2. Description of the Related Art
Since niobium has a dielectric constant about 1.8 times as high as that of tantalum, which is a material for conventional solid electrolytic capacitors, it draws attention as a material for next generation, high capacity solid electrolytic capacitors. Japanese Patent Application Laid-Open (JP-A) No. 07-153650 discloses a solid capacitor obtained by successively forming a solid electrolyte of manganese dioxide and a conductive layer for a cathode on an anode sintered body obtained by sintering a metal powder for valve action such as tantalum and niobium.
However, in the solid electrolytic capacitor disclosed in JP-A No. 07-153650, since the conductivity of manganese dioxide is low, there occurs a problem that ESR (equivalent series resistance) becomes high.
JP-A No. 5-136005 discloses a technique of forming a conductive polymer layer by electrolytic polymerization on a manganese dioxide layer. However, by this technique, ESR could not decrease sufficiently.